128680561 has 16 divisors (see below), whose sum is σ = 139536000. Its totient is φ = 118343808.

The previous prime is 128680549. The next prime is 128680567. The reversal of 128680561 is 165086821.

It is a cyclic number.

It is not a de Polignac number, because 128680561 - 2⁵ = 128680529 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (37).

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 128680561.

It is not an unprimeable number, because it can be changed into a prime (128680567) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 74890 + ... + 76588.

It is an arithmetic number, because the mean of its divisors is an integer number (8721000).

Almost surely, 2^128680561 is an apocalyptic number.

It is an amenable number.

128680561 is a deficient number, since it is larger than the sum of its proper divisors (10855439).

128680561 is a wasteful number, since it uses less digits than its factorization.

128680561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1848.

The product of its (nonzero) digits is 23040, while the sum is 37.

The square root of 128680561 is about 11343.7454572994. The cubic root of 128680561 is about 504.8600219822.

The spelling of 128680561 in words is "one hundred twenty-eight million, six hundred eighty thousand, five hundred sixty-one".